Also, is there even any need to tell people that parts aren’t copyrighted? That’d be pretty tedious to do (“texture on model pot_interior_clay_2_cracked is not copyrighted”). But if a game has a mix of copyrighted and non copyrighted media, that basically means nobody can use the non copyrighted parts because they simply can’t identify which parts those are.

I suspect there’s no need to tell people. After all, mixed media is already a thing. I can make a copyrighted video, for example, in which I quote some Shakespeare. The Shakespeare quote isn’t copyrighted, but the rest is. I’ve never seen any kind of copyright notice mention this.

So the net result might not be any different. Just if you steal assets from something, they might have a harder time identifying if they have a case of copyright infringement. Only if something was entirely AI generated would things likely change much. Though there’s also some weird edge cases. Like what if a human makes a 3D model but an AI textures it. 3D models are basically never used without their texture. So what’s the copyright implications of using videos of this textured model? Perhaps something for a very expensive legal case to figure out?